The invention relates to a guiding device for an areal printing material with a substantially two-dimensional structure, such as a sheet material, the guiding device having a guide surface facing the printing material. The invention further relates to a sheet-processing machine, in particular a rotary printing machine, equipped with such a guiding device.
A guiding device of the aforementioned type is disclosed, for example, by the published German Patent Document DE 196 02 514 C1. As this document discloses, high requirements are placed on guiding devices for sheet printing materials, and in fact, particularly on the guide surface formed thereon. They must be made especially smooth. Guiding devices used by the applicant therefore have a high-gloss polished guide surface. This requires particularly careful procedures in the production and handling of a conventional guiding device and, therefore, involves the risk of a given rate of wastage.
It is accordingly an object of the invention to provide a guiding device of the type mentioned in the introduction hereto, which can be produced with a possible wastage or reject rate that is considerably reduced.
With the foregoing and other objects in view, there is provided, in accordance with one aspect of the invention, a guiding device for an areal printing material, the guiding device having an areal structure with a guide surface facing towards the printing material, the areal structure comprising a supporting layer, and a surface layer is included for forming the guide surface and covering the supporting layer.
In accordance with another feature of the invention, the guiding device includes at least one support which, together with the supporting layer, forms a subassembly.
In accordance with a further feature of the invention, the support is trough-like in structure, has feed and discharge openings, and is otherwise closed by the supporting layer.
In accordance with an added feature of the invention, the support and the supporting layer are sealingly joined to one another.
In accordance with an additional feature of the invention, the support has a trough base formed with elevations, and the elevations are joined to the supporting layer.
In accordance with yet another feature of the invention, the support and a respective one of the elevations, on the one hand, and the supporting layer, on the other hand, are sealingly joined to one another and, in a region of a respective one of the elevations, are formed with apertures communicating with one another, the surface layer being formed with openings communicating with the apertures.
In accordance with yet a further feature of the invention, the guiding device comprises a chamber arrangement forming domes due to the elevations of the trough base.
In accordance with yet an added feature of the invention, the surface layer is provided with nozzles, a respective one of the nozzles, on the one hand, forming one of the openings in the surface layer and, on the other hand, extending into one of the apertures formed in the supporting layer, which communicates with one of the openings.
In accordance with yet an additional feature of the invention, a respective one of the nozzles forms a shaped region of the surface layer.
In accordance with a concomitant aspect of the invention, there is provided a rotary printing machine having a guiding device for an areal printing material, the guiding device having an areal structure with a guide surface facing towards the printing material, the areal structure comprising a supporting layer, and including a surface layer forming the guide surface and covering the supporting layer.
In one configuration of the guiding device according to the invention, the supporting layer forms an underlayer for the surface layer forming the guide surface, and therefore does not have to rest smoothly on the surface layer over the entire area. In particular, the surface layer, in preferred improved constructions thereof, is shaped so that, in spite of a relatively small layer thickness, it has a dimensional stability which is sufficient for the requirements and, for example, fixing lugs molded on integrally or in one piece, whereas according to a further development, at least one support is provided which, together with the supporting layer, forms a subassembly.
The supporting layer can have deformations, for example, which are directed away from the surface layer covering the supporting layer and are formed as beads, so that, in particular, in the case of one development, wherein a support is provided that is joined to the sheet-like structure via a fastening on the supporting layer, at the bottom of the respective bead, the most varied types of connections or joinings of the supporting layer to a support are possible, without affecting the guide surface in any way thereby. Instead, the surface layer forming the guide surface bridges over the aforementioned beads and/or other irregularities or discontinuities which may be in the surface of the supporting layer facing the surface layer. In particular, therefore, the supporting layer can be screwed or welded to a support, at the base of appropriate beads on the supporting layer, to form a subassembly. However, welding the supporting layer to a support is possible even without the formation of beads in the supporting layer, even in the case of a given build-up of corresponding welds on that surface of the supporting layer which faces the surface layer, because a build-up which may have an effect upon the course of the surface layer can be ground off before the supporting layer is covered by the surface layer.
In a configuration according to the invention of the guiding device mentioned at the introduction hereto, in particular, no increased requirements are thus placed on the supporting layer, to the extent that it is the condition of a surface of the supporting layer which is covered by the surface layer.
The process of producing the aforementioned subassembly, therefore, does not require any special measures to protect surfaces of the parts belonging to the subassembly. Appropriate measures are required only during the completion of the guiding device, by covering the supporting layer by the surface layer, and the further handling of the completed guiding device. In the event of any damage which may occur to the guide surface in the process, such damage is restricted to replacing the surface layer so that costs arising from any reject, wastage or spoilage are noticeably lower than in the case of rejects during the production of conventional guiding devices.
In an advantageous improvement, the support is trough-like, it has feed and discharge openings and is otherwise closed by the supporting layer. If, in addition, a support of such a construction and the supporting layer are preferably sealingly joined to one another, a chamber results, through which a cooling liquid can be pumped. A guiding device constructed in such a way is therefore suitable for guiding a sheet printing material along path sections wherein heat is transferred onto the guiding device from a dryer.
In a preferred improvement, the aforementioned trough-like support has a trough base provided with elevations, and the elevations are joined to the supporting layer. Therefore, even with a relatively thin-walled construction of the supporting layer and of the support, the subassembly formed therefrom proves to be relatively stable dimensionally.
If, according to a preferred development of the support, the supporting layer and a respective one of the elevations of the support are sealingly joined to one another, the supporting layer, on the one hand, and a respective one of the elevations, on the other hand, in the area thereof, are provided with apertures which communicate with one another, and openings which communicate with the apertures are provided in the surface layer, then the aforementioned cooling liquid, as it flows through the chambers formed by the supporting layer and the support, is advantageously ducted straightforwardly so that, on the supporting layer and on the support, areas that are not in contact with the cooling liquid are formed and surround a respective one of the apertures, so that the support and the supporting layer, and therefore also the surface layer, permit a throughput through the apertures thereof of a fluid which is separate from the cooling liquid. In this case, the elevations in the trough base preferably constitute cup-like depressions which are indented in the trough base from the outside thereof.
The aforementioned fluid is then preferably gaseous and is formed of ambient air in an available or in a conditioned state and, for the purpose of the ducting thereof, provision is moreover preferably made of a chamber arrangement through which the fluid flows during operation and which, due to the elevations in the trough base, forms domes. In this case, conditioned ambient air is to be understood in particular to mean that this air is, for example, dried and/or warm and/or carries powder with it.
Depending upon the use of the guiding device, the flow through the chamber arrangement takes place in such a manner that blown air flows out of the openings provided in the surface layer, or in such a manner that these openings are connected to a vacuum source, or in such a manner that a number of these openings are connected to a vacuum source while blown air emerges from the remaining openings. For the last case, the chamber arrangement is subdivided into corresponding excess pressure chambers and vacuum chambers. A chamber arrangement in the form of a multiplicity of separate individual chambers is preferably also provided for the case wherein the openings provided in the surface layer are penetrated, in particular, in groups, by different volume flows, it then being the case that a respective group of the openings communicates with at least one of the individual chambers.
In a further improvement, the surface layer is provided with nozzles. A respective one of the nozzles, on the one hand, forms one of the openings in the surface layer and, on the other hand, extends into one of the apertures communicating with one of the openings. These nozzles are furthermore preferably formed by shaping the surface layer, so that they are joined to the surface layer integrally or in one piece. Overall, therefore, a guiding device provided for a sheet printing material is produced by a manufacturing process which can proceed to the greatest possible extent without taking special account of surface qualities. This is because particular care with a view to the protection of surfaces is required only when forming the openings provided in the surface layer and when fitting or applying the surface layer to the supporting layer.
Because of the one-piece connection or joint between the nozzle and the surface layer, it is moreover possible to achieve a continuous transition between the guide surface and a region of the surface layer that forms a respective one of the nozzles. In particular, in the region of the nozzles, no joints or steps result, which otherwise would be inevitable if separate nozzles were to be inserted into the guiding device.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a guiding device for an areal printing material, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.